Wednesday, May 03, 2006

Increasing Oil Supply

Novel extraction technologies could as much as double accessible world oil.

By Kevin Bullis

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Rapidly heating many rock types causes them to break apart. This process could be the basis for a new, less expensive method of drilling for oil. (Photo courtesy of Jefferson Tester, MIT.)

The amount of accessible oil worldwide could eventually be increased by roughly 30 percent with the help of new drilling, imaging, and oil extraction technologies, including the use of microbes, say MIT researchers. Theoretically, this number could be even higher; in a best-case scenario, the amount of oil that could be produced would double.

On average, using current techniques, about two-thirds of the oil in an oil field gets left behind, says Richard Sears, a vice president at Shell International Exploration and Production, Houston, TX. "The fundamental problem is basic physics. It's not like the oil is in big tanks. We produce oil from rock -- sandstone. The oil is actually held in the very small spaces between the grains of sand. The problem is, when you try to move that oil out of the rocks, because of the size of the spaces, you end up with a layer of oil coating the insides of the rocks." About one-third of the oil in fields will always be inaccessible. That leaves one-third that could be recovered with new technologies -- which is equal to the amount that would have already been extracted.

Getting all of this oil out would be extremely ambitious, but Robert van der Hilst, earth, atmospheric, and planetary sciences (EAPS) professor at MIT, says much smaller gains would still be marked improvements. Increasing the percent of oil harvested from worldwide oil fields by even one percentage point would be the equivalent of adding a new oil-producing region as productive as the fields in the entire North Sea, he says.

To a certain extent, getting more oil out of existing fields is a question of economics. Oil, which resides underground in porous rock, can be forced out by injecting water, steam, or carbon dioxide, but these methods bring added costs that limit their use. If oil prices stay consistently high, these methods will be employed more than they are now, Sears says.

But significantly increasing oil recovery will require new technologies. At the top of the list are better oil field imaging techniques, says Nafi Toksöz, an EAPS professor at MIT. Improved imaging can help oil companies find and tap areas in an oil field that have become surrounded by water, and so cut off from oil wells, he says. It can also improve the effectiveness of existing methods such as using water or steam to extract oil.

As it is now, water pumped into a field, for example, might start to cut a channel through the oil, and so, rather than pushing oil out, would simply enter through an injection well and flow out through an extraction well in the place of oil. Better understanding of the dynamics of an oil field through imaging at regular intervals can help engineers know where best to inject water and steam, and how to control the pressure to prevent channels from forming.

Increasing Oil Supply

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